‘Who are your people?'*

Pippa Goldschmidt is part of the ESRC Genomics Forum Writers team covering the Edinburgh International Book Festival 2011.

Yesterday Alistair Moffat talked about the genetic identity of the Scottish people and the emerging science of tracing our ancestors using DNA. This essentially uses mistakes in DNA (mutations that occur by chance) which are then propagated. If we share these mistakes with other people, we must share a common ancestor, and by looking at where these mistakes are the most common, we can find out where that ancestor originated. So, for example, a fifth of Irish men are related to a single man, Niall Noigiallach, who lived about 1500 years ago.

There are two ways of tracing these markers back through the generations, by examining the DNA on the Y chromosomes that men inherit from their fathers, and by examining mitochondrial DNA that both men and women inherit from their mothers.

Alistair Moffat said that people are quite often moved when they find out about their ancestry and their links to Vikings, or Celts, or Irish kings, as this allows them a way of imagining their pasts. But using Y DNA or mitochondrial DNA only gives us two routes back through the complex network of our ancestors; we may have proof that we’re descended from an Irish chieftain but we shouldn’t forget that we’re also descended from a zillion (roughly speaking) other people too.

Perhaps it’s not the differences, but what we share that is more important, and also more moving. In 75,000 BC a vast volcanic eruption led to mass extinctions of species, and killed off all but a handful of Homo sapiens, who escaped because they were living in the narrow rift valleys of East Africa. These humans emigrated north, and in a relatively few generations had established themselves in Asia and Europe. We’re all descended from those tenacious people.

* The Gaelic poet Sorley MacLean (see Ken’s blogs below) apparently asked this when he first met people.

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Originally from London Pippa used to be an astronomer. Now with an MLitt in creative writing from Glasgow University she has had several short stories published. Much of her writing is inspired by science and she is currently writing a novel about a female astronomer. Visit her website for more information www.pippagoldschmidt.co.uk